1. Field of the Invention
The invention generally relates to a digital video editing method and system and, more particularly, to a method and system for assembling an edited program from one or more digital video source material taken in from a video camera, storage media and/or transmission media by selecting and ordering segments (or scenes) of the video source materials.
2. Description of the Prior Art
U.S. Pat. No. 5,537,530 issued Jul. 16, 1996 discloses a typical method for editing video comprised of a sequence of video segments by locating segment boundaries and reordering segment sequences. Frames associated with sequences of video source material representing a series of scene changes are digitized. The digitized information is analyzed to identify one or more frames of the source material associated with and representative of each such scene change and/or sequence. The representative frames are displayed. A selected frame from the display will thereby cause automatic selection and association of a sequence of frames. The corresponding frames of video segments or scenes corresponding to each such selected and ordered representative frame are thereby automatically also ordered. Simplified video editing is accomplished by manipulating these representative frames, each associated with a different scene or video sequence.
U.S. Pat. No. 5,237,648 issued Aug. 17, 1993 discloses xe2x80x9cApparatus and method for editing a video recording by selecting and displaying video clips.xe2x80x9d In the editing system, the user is presented with a video window for displaying the video information, a control window for regulating playback of the video information, and a clip list window having a number of rows of edit windows organized under begin, end, and clip columns. The user can generate video clips and change the clips by clicking on the desired video frame to generate a small digitized version of the frame and moving the small digitized frame from the video window to an edit window.
U.S. Pat. No. 5,218,672 issued Jun. 8, 1993 discloses a post production off-line editing system for storing unedited video takes in a random access memory (a set of laser video disk players), displaying selected takes (or individual frames from selected takes) and generating an edit list which defines an edited video program. The user can include, in the edit list, definitions of various video transitions between scenes, such as dissolves, fades, and wipes.
However, prior art video editing systems provide only an editing method based on either selection or elimination of a specified video scene. In some cases, it will be desirable to specify and select a necessary portion, and in other cases, it may be desirable to specify and eliminate an unnecessary portion. It is therefore an object of the invention to provide a video editing system which permit the user to issue a desired one of selection and deletion commands for a specified object.
The above and other prior art video editing systems usually have a so-called undo function. Issuing some undo commands at a certain editing state causes the current editing state to be restored to the previous editing state by each of the issued undo commands. However, it may be sometimes desired to restore a specific scene to its last relative position in order with respective to the scene which was just before or after the specific scene in order before the specific scene has taken the current position. Therefore, it is another object of the invention to provide a video editing system having a restore function of restoring a specified scene to its last relative position in order with respective to the scene which was just before or after the specific scene in order before the specific scene has taken the current position.
In the above and other prior art video editing systems, a series of frames or a scene is dealt with as an editing unit (or a clip). However, there are sometimes two or more scenes that the user desires to manipulate as a single clip though the scenes are discontinuous in time or derived from different source videos. Therefore, it is further object of the invention to provide a video editing system which not only permits the user to group two or more scenes together to make the grouped scenes a clip but also provides various improved and novel functions such as enhance the user""s convenience and the efficiency of video editing.
According to the invention, a video editing system comprises a computer system provided with a mass storage and further provided or connected with one or more video source such as an optical disc player, video cassette recorder (VCR) and/or camera The computer system operates under the control of standard operating software and video editing software stored in the mass storage.
In preparation for a subsequent editing process, one or more source videos are first collected and stored as video source material in the mass storage. One or more of the stored source videos is (or are each) checked to generate scene records which define respective video segments constituting the source video(s). Scene records are also generated for the other source videos. Thereafter, the video segments and the other source videos are called xe2x80x9cscenesxe2x80x9d and dealt with by operating respective scene records.
The display screen of the system has at least one scene display area. The area is comprised of an array of windows for each displaying a frame representative of each of available scenes constituting the source videos (the frame is hereinafter referred to as xe2x80x9ca scene indexxe2x80x9d). The scenes are displayed in the area even if they are selected as clips for use in the video program.
In a preferred embodiment, the records are maintained as a scene table. Each record has at least the field of an ID and the length-in-number. Each record preferably contains begin and end frame numbers, a selection flag, a frame pointer for scene scrolling, a component scene IDs for grouping capability, a selected order for clip sorting in selected order, a clamp flag for scene clamping, and a transitional effect.
Simulation is conducted through manipulations of scene and clip indexes, e.g., segmentation, grouping, clipping, ordering, etc. Information on a series of such manipulations is accumulated in the scene table. Finally, a clip list is obtained. According to the clip list, an edited video program is compiled.
According to the principles of the invention, one or more frame of a user-specified scene or clip is displayed. Any frame of the scene is accessible by controlling forward and backward button and a scrolling bar. The value of a frame pointer is stored for each index, enabling a resume of viewing.
Specifying desired scenes or clips, the user can group the desired scenes or clips. In grouping, a scene record is added to the scene table. IDs of grouped scenes or clips are stored in a component field of the added record. An index for the group is added to an index set. The indexes for the specified indexes are deleted from the index set. The grouping is achieved either in order of time if the specified scenes or clips have been derived a single source video or in a specified order. Grouped scenes or clips are further grouped.
In an embodiment with two display areas for scenes and clips, once scenes are grouped, the grouped scene becomes a clip automatically. That is, the grouped scenes disappear from the scene display area, instead appear in a clip display area.
Also, in an embodiment with scene and clip display areas, a flexible index specifying function is provided. If the user specifies desired ones of the indexes, the desired ones are become in a specified state and the remaining indexes become in a nonspecified state. If the user enters a predetermined input at this point of time, the specified state and the nonspecified state are reversed.
Selection and unselection functions cause a scene and a clip to be changed to a clip and a scene, respectively. This functions can be applied to the same scene or clip at any times. Each time one of the two functions, predetermined fields (selected order fields in an illustrative embodiment) of the record are so updated that the selected order fields retain values indicative of the order of selection of respective scenes and clips. By doing this, the clips can be sorted in the selected order.
The clips can be sorted in order of time if the clips are derived from a single source video.
Each time a segmentation or a grouping is performed, predetermined fields (original order fields in an illustrative embodiment) of the records which each contain the order of the scenes are so updated that the fields of the records reflect the order of current scene indexes. If the user issues a predetermined command while specifying a desired scene index, then the specified scene index is restored to a relative position with respect to a scene index which the specified scene index was adjoining at a time of occurrence of a predetermined event. In a preferred embodiment, the event is a later one of a last segmenting and a last grouping. The user can select whether the specified scene index should be restored to a next-based relative position or a back-based relative position.
The video editing system is further provided with a function for causing a start time, in the edited video, of a user-specified one of the video segments (derived from a single source video) to be the same as that in the single source video (hereinafter referred to as xe2x80x9cclamping the user-specified video segment to the single source videoxe2x80x9d). For this purpose, the user can issue a command to clamp a specified video, causing a flag to be set in a predetermined field of a record associated with the specified video. Then, in a compiling process, a scene just preceding the specified video is so trimmed that an end frame number of the preceding scene in a program being compiled is smaller by one than a value of a begin frame field of the record associated with the specified video.
Also, the user can set one of predetermined transitional video effects to an effect-containing field of a record associated with a user-specified index. Then, an effect identified by the effect-containing field is applied to the video segment associated with the user-specified index.